2011 Census: Lessons learned from the Business Sector

1. 2011 Census: Lessons learnedfrom the Business Sector Dr Barry Leventhal MRS Census & Geodemographics Group CAG Meeting 8th January 2015

2. 2011 Census – Worked well • Consultation on the questions (despite income not being included) • Fieldwork and response rates • Geography products – boundaries, directories, etc. • Bulk output format • Consistent set of univariate statistics across the UK at OA level • Workplace zones • Helpfulness of ONS and NRS in resolving issues with table specifications

3. 2011 Census – What caused problems? Primarily, the implementation of SDC in practice, resulting in... • Detailed design and agreement of tables being delayed • Lack of transparency in changes to outputs made by the Census Offices • Late changes made by ONS were not always adopted by NRS or NISRA • Inconsistency in UK outputs - Local Characteristics tables • Safeguarded data specs & access plans were put back • In consequence, the delivery of outputs has taken nearly 4 years

4. Statistical Disclosure Control issues • Move to pre-tabular record swapping removed inconsistencies between tables • However, tables that were non-disclosive in 2001, became disclosive in 2011 • Therefore many tables had to be redesigned, losing detail that available previously • All tables had to be checked – SDC became a bottleneck • SDC rules had to be relaxed in order to produce key tables (e.g. Age x Sex at OA level) – disclosure method should be been designed with key outputs in mind at the outset

5. Detailed design and agreement of tables earlier in the process • Detailed table specs used to be produced in advance of the Census – so users knew exactly what would be produced • Output requirements were gathered, but detailed design of tables was pushed back – seemed to suffer from changes in personnel / insufficient resources? • Table specifications could not be released to users until SDC checks had been completed – so users only discovered layouts when tables were published

6. Lack of transparency in changes to outputs made by the Census Offices • Late changes in table designs were made by ONS topic leads, e.g. adding 3rd variable to a 2-variable table • This necessitated further SDC checking, with collapsing of (say) age groups, resulting in unusable table – worst cases were raised at emergency meeting with ONS in February 2014, and were resolved • Better to produce 2-way tables with greater detail than 3-way with insufficient detail • Topic leads should not make late changes to specifications without properly consulting users

7. Greater consistency in UK outputs - Local Characteristics tables • Late changes in LC tables made by ONS were not always carried through to NRS and NISRA • e.g. improvement in age bands were not always matched by NRS • Northern Ireland output omitted certain themes • e.g. students, dependent children, second homes, former industry, distance travelled to work, migration • Variables were therefore not populated across the UK and could not be used in geodemographic classifications

8. Commercial access to Origin/Destination safeguarded data • ONS current view is that safeguarded O/D data carries a greater perceived disclosure risk and will only be available to commercial users in a secure environment – infeasible for most commercial users • Most business needs would be met by top-line flow counts - how is this data potentially disclosive, when no attributes are revealed? • ONS policy discriminates against commercial users and creates unfair advantage for some other users • Situation is anomalous - all other Census outputs are either Open or have similar access for all

9. Speed and order of output processing • Despite technology advances over the decades, speed of census delivery does not seem to have improved • “Long tail” in producing final outputs in 2014 – due to wind-down in census resources? – but “the last 100 yards is the most important” • Priority tables should be agreed in future, e.g. • univariates (by OAs), for each country and UK • Age by Sex by Residence type (for OAs) • What improvements can be made for 2021, when c. 60%-70% of data will be captured online? • Perhaps an early release could be considered based on internet completion? • Business users would welcome an ONS feasibility study into making a dramatic improvement in delivery times, setting an ambitious target and looking at all processes to see what could be achieved – on a timescale to implement findings for 2021

10. The major lesson to be learned for 2021:Don’t let SDC be a bottleneck on outputs again • Increase staff resources devoted to output design & SDC considerations in the short term (a very small part of the total Census budget) • Build on the ultimate table specs developed for 2011 – a starting point • Focus on the needs of users / customers, and how close the SDC team can get to meeting their needs • Aim to get all the outputs published much more swiftly, and don’t change the staffing until this is complete Recommendation: • ONS should conduct a more wide-ranging feasibility study of producing outputs sooner next time around and publish the results of that study 

11. Thank you! Dr Barry Leventhal 07803 231870 barry@barryanalytics.com